Influenza pandemic of 1918

The Influenza pandemic of 1918 was a heavy pandemic of influenza. It lasted from January 1918 to December 1920.[1] About 500 million[1] people were infected across the world. The pandemic spread to remote Pacific Islands and the Arctic. It killed 50 million[2] to 100 million people[3]—3 to 5 percent of the world's population at the time.[3] This means it was one of the deadliest natural disasters in human history.[1][4][5][6]

To maintain morale, wartime censors minimized early reports of illness and mortality in Germany, Britain, France, and the United States;[7][8] but papers were free to report the epidemic's effects in neutral Spain (such as the grave illness of King Alfonso XIII). This situation created the false impression of Spain being especially hard-hit.[9] It also resulted in the nickname Spanish flu.[10]

In most cases, influenza outbreaks kill young people, or the elderly, or those patients that are already weakened. This was not the case for the 1918 pandemic, which killed predominantly healthy young adults. Modern research, using virus taken from the bodies of frozen victims, has concluded that the virus kills through a cytokine storm (overreaction of the body's immune system). The strong immune reactions of young adults ravaged the body, whereas the weaker immune systems of children and middle-aged adults resulted in fewer deaths among those groups.[11]